[Charcot-Marie-Tooth disease: electromyography is still useful in diagnosis and classification]

Genetic heterogeneity was known for a long time in Charcot-Marie-Tooth disease (CMT). The recent findings in molecular biology emphasized the distinction in different types of the disease. Nevertheless, electrophysiological examinations are of a great interest to detect asymptomatic patients, to classify the different forms and to make correlations with the clinical and histological features. Current classification is based on genetic and electrophysiologic data. CMT1, or hypertrophic form in which mutations or a duplication were found on chromosome 17 is the most frequent (CMT1A), CMT2 is the neuronal form, CMT3 is termed the Dejerine-Sottas disease, CMT4 recessive forms, CMT5 a form with associated pyramidal features, and CMTX. The electrophysiologic aspects of these different types are reported.